Remove listener for Johnny-Five event in Node.js

I'm using Johnny-Five to work with a passive infrared detector and a C.H.I.P. Linux, single-board computer. Everything works fine in general.

But say I've defined a pin and a button, like this:

let button = new five.Button({
  pin: 'XIO-P0'
});

let pir = new five.Pin({
  pin: 'PWM0',
  type: 'digital',
  mode: 0
});

And at some point I decide to listen to read events and button presses like this:

button.on('press', function() {
  console.log('Button pressed');
});

pir.read(function (error, value) {
  if (error) {
    console.log('Error:', error);
  } else {
    console.log('Pin:', value);
  }
});

How do I tell Johnny-Five that I no longer want to listen to that event? I can't, for the life of me, find it mentioned anywhere in the docs or on Google.

Any help would be appreciated.

Solution

So it turns out that Button extends the Node.js EventEmitter object. As such you can use the removeListener() and removeAllListeners() methods associated with it. But it seems to require that you define your callbacks as non-anonymous functions so that you can refer to them for removal.

button.on('press', buttonPressCallback);

function buttonPressCallback() {
  console.log('Button pressed');
}

The Pin.read() function doesn't work the same way, so if you want to be able to kill it off in the same way, you need to use the event interface for Pin. There are high, low, and data events. Data does all changes.

pir.on('high', pinHighCallback);

pir.on('low', pinLowCallback);

function pinHighCallback() {
  console.log('Pin: HIGH');
}

function PinLowCallback() {
  console.log('Pin: LOW');
}

So now to remove these listeners we would just call the following:

button.removeListener('press', buttonPressCallback);
pin.removeListener('high', pinHighCallback);
pin.removeListener('low', pinLowCallback);